Liquid dispensing assembly with improved filling means



20, 1969 J. 5. CAMPBELL ET-AL 3,445,041

LIQUID DISPENSING ASSEMBLY WITH IMPROVED FILLING MEANS Filed Oct. 5.1966 IN VEN T035 JAMES SAMUEL CAMPBELL W/LFRED ERNEST WILLIS BY WARREN,BROSLER, GYPHER 8 AN 6L M! A T TOR/V575 United States Patent 3,445,041LIQUID DISPENSING ASSEMBLY WITH IMPROVED FILLING MEANS James SamuelCampbell, Orinda, and Wilfred Ernest Willis, San Francisco, Calif.; saidCampbell assignor to Campbell Auto-Pour Engineering, Berkeley, Calif., acorporation of California Filed Oct. 5, 1966, Ser. No. 584,547 Int. Cl.B6741 /02, 5/54 U.S. Cl. 222-152 2 Claims ABSTRACT OF THE DISCLOSUREDispensing of molten metal from a furnace by applying inert gas pressureto said furnace to force the metal out of a tube, and further applyingsaid gas to the tube.

Our invention relates to apparatus for the dispensing of liquid and moreparticularly to the filling of such apparatus with liquid to bedispensed, with special application of the invention in the dispensingof molten metal from a furnace or receptacle in the casting of molds,and will be described in its preferred form with respect to suchapplication.

For some die-casting and permanent rnold applications and some otherapplications, it becomes desirable to recharge, or refill, the furnaceor equivalent receptacle without interrupting the pattern of dispensingoperations. For example, in die-casting or permanent mold casting, thedies or molds are kept heated to the correct operating temperature rangeby the liquid metal which is poured into them. Once the proper timeinterval between pouring has been determined, this pouring patternshould be maintained during operation. If this pattern is interrupted ordelayed, the die or mold may cool to below its proper operatingtemperature range. Then, the next casting or castings will probably bedefective until the die or mold again reaches its proper operatingtemperature.

Such interruption or delay in the pouring pattern may, in a conventionalsetup, be due to the necessity of occasionally recharging or refillingthe furnace. And if the furnace be pressurized, replenishing of the samewith prevailing type of equipment, must of necessity cause aninterruption in the dispensing of contents therefrom.

Among the objects of our invention are:

(1) To provide novel and improved apparatus for the dispensing ofliquid, having improved filling means which will not necessitate aninterruption or alteration of a prevailing pouring pattern,

(2) To provide novel and improved liquid dispensing apparatus of thepressurized type, having means permitting filling thereof withoutinterrupting or altering dispensing operations,

(3) To provide novel and improved pressurized furnace assembly orequivalent, for dispensing of molten metal protected by inert gas, suchnovel and improved pressurized furnace assembly incorporating means forrecharging a furnace in a very simple and convenient manner with moltenmetal, while minimizing contamination of the metal entering the furnace,

(4) To provide novel and improved means for enabling filling of apressurized liquid dispenser through a stand pipe arrangement.

Additional objects of our invention will be brought out in the followingdescription of a preferred embodiment of the same as applied to thedispensing of molten metal, taken in conjunction with the accompanyingdrawing, wherein, the figure is a schematic diagram of a pressurizedfurnace assembly utilizing inert gas as the pressuring medium, andincorporating the improved filling means of the present invention.

Referring to the drawing for details of our invention in its preferredform as applied to the dispensing of molten metal, the same comprises afurnace 1 having a cover 3 adapted to be sealed in place, and a pourpassageway in the form of a pouring tube 5 extending from a low pointwithin the furnace, below the normal liquid level range therein, to ahigh point at its discharge end 7, above the maximum contemplated liquidlevel within the furnace. At its discharge end, it preferably connectswith a downwardly directed nozzle or equivalent 9, in a structureforming a small chamber 11 above the junction with the nozzle.

The specific furnace illustrated is one of the pressurized typeproviding a gas chamber 12 above the molten metal therein. Pressuringgas is introduced into the furnace through a tube 13, enteringpreferably through the cover of the furnace and terminating at a pointbelow the normal liquid level range in the furnace, whereby gas enteringthrough the tube will exit from the lower end thereof and percolate upthrough the molten metal into the gas chamber to develop pressuretherein. This form of gas intake is employed where the gas is of aninert type, such as nitrogen or argon, which is capable of degassing themetal as it percolates up therethrough.

Gas pressure in the chamber is preferably built up to a value sufficientto raise a column of molten metal in the pouring tube, to an elevation14, approaching the high or discharge point thereof, where it will beready to pour upon development of a slight increase in pressure. Suchincrease in pressure should be suflicient to raise the molten metal toan elevation 15 within the small chamber 11, above the junction of thepouring tube and nozzle, to assure a full constant flow of molten metalat the higher or pour pressure.

It is characteristic of this furnace, as disclosed in the application ofWilfred Ernest Willis for Pressure Pour Apparatus, Ser. No. 524,955,filed on Nov. 30, 1965, issued on Oct. 17, 1967 as US. Patent No.3,347,427 that the externally applied pressures will not requirechanging, despite changes in gas pressure within the furnace with changein liquid level therein. This characteristic enables an operator tocontrol operations of the furnace with two discrete pressures, namely, aready-to-pour" pressure sufficient to maintain the level in the pouringtube at the ready-to-pour level 14, and a pour pressure of just slightlyhigher value, sufficient to raise the level to the pour level 15 withinthe chamber 11, as previously mentioned.

A gas flow line 17 from the gas chamber 12 in the furnace, to thechamber 11, is provided, to protect the metal in the pouring tubeagainst oxidation and other sources of contamination, the flow throughthis connection being controlled by a valve 19, adjusted to limit flowto a value of the order of a leak.

The ready-to-pour and pour pressures may be applied to the furnacethrough the degas tube 13 exclusively, as described in theaforementioned Willis application, but for a quicker build up ofpressure within the furnace, some of the gas may be fed directly intothe gas chamber of the furnace at appropriate time in the operation ofthe furnace, in accordance with the teachings of the application ofRobert B. Rice, Jr. for Gas Feed to Pressure Pour Apparatus, Ser. No.564,953, of July 13, 1966, US. Patent No. 3,395,833, issued Aug. 6,1968.

In accordance with this latter method of feeding gas to the furnace, dryinert gas from a pressure tank 23 is reduced through a pressureregulator 25 to a value capable of being readily handled by the systemof the present invention. Such value will necessarily be somewhat abovethe pour pressure value. The gas is supplied to a manifold 27, fromwhich a connection 29 feeds a pair of branch lines 31, 33, one of whichconnects to the degas tube 13, and includes a pressure regulator 35adjusted to the ready-to-pour pressure value, and made responsive to thepressure in such line.

The other branch line 33 leads directly to the gas chamber in thefurnace, preferably by coupling into the leak flow line 17, and includesa pressure regulator 41 adjusted to the pour pressure value, and maderesponsive to the prevailing pressure in the first branch line 31,downstream of the ready-to-pour pressure regulator 35.

A normally closed solenoid operated valve 43 in the line 29 connectingto the branch lines, may be energized to open position, to condition thefurnace for operation, while a normally closed solenoid operated valve45 in the pour pressure branch line 33, may be energized to its openposition, to initiate a pouring operation following establishment of the'ready-to-pour pressure in the degas tube. Such opening of the pourpressure line will supply gas at this pressure directly into the gaschamber of the furnace until the build up of pressure in the furnace,reacting through the degas tube, causes the pour pressure regulator toshut off.

Thus, dispensing of molten metal through the pouring tube will commenceupon opening of valve 45, and as the pressure within the furnace tendsto drop with such discharge of metal, the pour regulator 41 will openand bring the pressure back up to a value which will cause the reactivepressure through the degas tube to again close off the pour regulator,and such cycling of the pour regulator will continue with discharging ofmetal from the furnace.

Upon completion of a pour operation, restoration of ready-to-pourpressure may be accomplished by momentarily opening the leak line 17 toatmosphere or an accumulator (not shown), through a normally closedsolenoid controlled valve 47.

A second line 49 from the manifold to the degas tube, includes athrottling valve 51 adapted to limit flow to a leak value slightly belowthe leak flow from the gas chamber. This leak flow line to the degastube includes a normally open solenoid controlled valve 53 which remainsopen during pouring and during non-pressurized condition. It is closedduring ready-to-pour conditions.

In the operation of a furnace assembly without the present invention,filling is accomplished through the opening of a door 57 in the cover orroof of the furnace, and inas much as this procedure exposes the gaschamber to atmosphere, pressure conditions change, and consequently, allpouring operations have to cease while the furnace is being recharged.

In accordance with the present invention this is no longer necessary,for we provide a filling tube preferably in the form of a stand pipe 57,extending from a point in the furnace or receptacle, below normal liquidlevel range, to a high point above the pour passageway or pouring tube5, such stand pipe preferably extending through the cover of thefurnace, in which it is sealed.

When so installed, the molten metal will rise in the stand pipe to thesame level to which it rises in the pouring tube, and due to the columnof liquid thus formed in the filling tube, no gas may escape from thefurnace through this tube.

As it becomes necessary to recharge or replenish a furnace so providedwith a filling tube, all one need do, is pour such metal into the tube.Due to the fact that the column of liquid in the filling tube cannotrise above that prevailing in the pouring tube, metal will exit from thebottom of the tube to raise the level in the furnace.

Should recharging be undertaken during a ready-topour condition, thetendency for the infiowing metal to slightly raise the prevailing gaspressure in the furnace, could conceivably cause a slow but temporarydischarge 4 from the pouring tube. This could be alleviated by operatingthe furnace at a lower ready-to-pour level.

In the alternative, the leak flow could be increased to compensate. Thismay be realized by shuntting the leak valve 19 by a line 59 including aleak valve 61, adjusted for greater flow, and a normally closed solenoidcontrolled valve 63 which may be under operator control. Duringrefilling, the operator could temporarily increase the leak flow andthus preclude such build up of pressure. A pressure gauge 65 connectedinto the leak fiow line 17 will enable an operator to readily accomplishsuch pressure control.

To facilitate the adding of molten metal to the furnace in this manner,a funnel 67, may be added to the filling tube, and it in turn may befitted with a cover 69, either hinged or sliding, preferably the latter,whereby to seal off the column of molten metal therein from continuousexposure to the atmosphere.

Where the pressure gas is of the inert type, to blanket the molten metalin the furnace as well as the pouring tube with a protective covering ofgas, we provide means for similarly protecting the molten metal in thefilling tube.

We have accomplished this by installing in the sliding cover, a hoseconnection fitting 71, which by means of a flexible hose coupling 73, isconnected to a flow line from the manifold, said flow line including amanually adjustable throttle valve 77 which is closed sufficiently toprovide a leak flow through the line to maintain a blanket of such gasover the metal. Also included in such line is a solenoid controlledvalve 79 of the normally closed type.

Coupled to the same flexible hose connection, is a gas feed line 81extending from the leak flow line 17, and in this connection, is anormally closed solenoid controlled valve 83, which when opened, willpermit flow of gas to the filling tube from the gas chamber 12 in thefurnace, via the leak flow line 17.

The solenoid controlled valve 79 in the How line to the filling tubefrom the manifold, is energized to be held open during ready-to-pourcondition of the furnace, and is deenergized to its normally closedcondition during a dispensing operation.

While a dispensing operation is in progress, gas feed to the fillingtube is preferably switched over to the leak fiow line, by deenergizingsolenoid valve 79 and simultaneously energizing the solenoid controlledvalve 83, and this, in turn, is made responsive to a slight build up inpressure in the chamber 11 above the nozzle, occuring at the start of apouring cycle as the molten metal rises into such chamber. A pressureswitch 84, coupled into the leak flow line adjacent this chamber, is setto respond to such slight rise in pressure to adjust the solenoidcontrolled valves in question, along the lines disclosed in theaforementioned Willis application.

In lieu of switching from line 75 to line 81 during pour, the line 75may be permanently maintained in flow connection with the filling tube,while the line 81 may be flow coupled to a mold during pour as depictedin the Willis application, in which case, the solenoid valve 79 may beremoved.

The filling tube embodied in the present invention as described,provides a very simple and convenient way of recharging a furnace orequivalent receptacle with molten metal to be dispensed, and suchfilling operation may be undertaken at any time, without adverselyinterfering with the dispensing of metal from the furnace, particularlywhere the dispensing of the contents of the furnace may be by gaspressure, for the liquid column supported in the filling tube, functionsas a pressure seal to block escape of such gas.

A melt-down furnace which might conceivably be employed in supplyingrefill metal to the furnace, could conceivably be more suitable forrapid melting, and metal supplied from such furnace for refilling thepresent furnace, probably would not be thoroughly degassed and cleansedby the time it is introduced into the filling tube. After entering thefurnace, however, such added metal becomes exposed to the degassingprovided by the inert gas entering the degas tube, and thus can bethoroughly purified while awaiting dispensing.

In lieu of employing a separate or independent filling tube asillustrated as described, the filling tube may be coupled into thepouring tube, which would efiect some economy, and might be preferred,where the metal supplied to the furnace meets quality requirements, forsome of that metal, during dispensing, might mix with the metal beingdispensed, without entering the furnace interior, and therefore shouldbe of a quality satisfying the prevailing requirements for purity.

The term normal level range as employed herein, represents thedifference between the level to which the furnace would normally befilled and the level at which recharging of the furnace would normallybe undertaken. Neithter level is deemed critical.

From the foregoing description of our invention, it will be appreciatedthat the same fulfills all the objects attributed thereto, and while wehave illustrated and described the same in considerable detail, it willbe apparent that the same is subject to alteration and modificationwithout departing from the underlying principles involved, and weaccordingly do not desire to be limited in our protection to thespecific details so illustrated and described, except as may benecessitated by the appended claims.

We claim:

1. A furnace assembly comprising a receptacle for liquid and having apour passageway extending from a low point therein below normal liquidlevel range, to a high point above such normal liquid level range,

a filling tube extending from a point in said receptacle below normalliquid level range to a high point above the high point of said pourpassageway,

means providing a gas chamber in said receptacle above said liquid,

means for conducting gas under pressure to said chamber,

means for controlling the gas pressure in said chamber,

said last named means including means connectible to a source of inertgas under pressure, for selectively feeding said inert gas to saidreceptacle at either a low pressure sufficient to elevate liquid in saidpour passageway to a ready-to-pour elevation, or a higher pressuresufficient to elevate liquid in said pour passageway to a pour elevationto initiate a pour cycle, and

means for conducting some of said inert gas to said filling tube.

2. A furnace assembly as recited in claim 1, characterized by meansconducting some of said gas to the high point of said pour passagewayduring a ready-to-pour condition, and means for switching said gas fromsaid pour passageway high point to said filling tube during a pourperiod.

References Cited UNITED STATES PATENTS 12/ 1965 Shearman 222394 X l/l966Holz et al 222397 X US. Cl. X.R.

